#include <stdio.h>

int SumToNum(int start, int end)
{
  int sum = 0;
  for(int i = start; i < end; ++i)
  {
    sum += i;
  }

  return sum;
}

int main()
{
  int start = 1;
  int end = 100;
  int sum = SumToNum(start, end);

  printf("sum = %d", sum);

  return 0;
}
